Personally, I wouldn't bother with having a "most accurate" SQL, as most databases need to rewrite the whole row anyway.

doesn't do what you think it does, so it might help if you showed us the actual error message that Perl tells you.

If you're bent on providing a "most accurate" SQL statement, most likely the following code can give you such a statement:

use strict;
my @columns = qw(name title state);
my @input = qw(foo bar baz);
my @inputUpdate = qw(boing bar boo);

my $table_name = 'mytable';

my @new_value_clause = map { "$columns[$_] = ?" } grep { $input[$_] ne
+ $inputUpdate[$_] } 0..$#inputUpdate;
my @where_clause     = map { "$columns[$_] = ?" } 0..$#input;

my $sql = join "\n",
         "UPDATE $table_name",
         "SET " . join ",", @new_value_clause,
         "WHERE " . join " and ", @where_clause;

my $sth = $dbh->prepare($sql);
$dbh->execute(@inputUpdate, @input);
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